In this study, two new antimicrobial flavonoid compounds were isolated and characterized, and their biological activities were assayed. The pure antimicrobial compounds were isolated and characterized from the ethyl acetate extract using different chromatographic techniques. The antimicrobial activity of the isolated pure compounds was assessed using disk diffusion method. Phytochemical investigation on the ethyl acetate crude extract of stem of Adenium obesum ( A. obesum ) resulted in the isolation of two pure new flavonoids 5,7,3′,4′-tetrahydroxy flavone 1 and 3,5,7,3′,4′,5′-hexahydroxyflavone 2 with several other minor compounds. Their structures were deduced on the basis of 1 H NMR, 13 C NMR, DEPT 90 and 135, COXY, HMBC, and MS. The pure antimicrobial flavonoid compounds showed significant antibacterial activities against Staphylococcus aureus , Escherichia coli , Pseudomonas aeruginosa , and Proteus vulgaris in the disk diffusion assay. Inhibition zones were 9–14 mm. The maximum inhibition was shown by compound 2 at concentration 200 μg/ml against P. vulgaris (IZ = 14 mm) when compared with the standard amoxicillin. The results showed that the isolated pure antimicrobial flavonoid compounds have significant antimicrobial activity, which can be used as antibiotics. This is the first report on isolation of these secondary metabolites from A. obesum .
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机译：在这项研究中，分离并表征了两种新的抗菌类黄酮化合物，并对其生物学活性进行了测定。使用不同的色谱技术从乙酸乙酯提取物中分离出纯净的抗菌化合物并进行表征。使用圆盘扩散法评估分离出的纯化合物的抗菌活性。通过对植物叶den（A。obesum）的乙酸乙酯粗提物进行植物化学研究，分离出两个纯的新黄酮5,7,3'，4'-四羟基黄酮1和3,5,7,3'， 4'，5'-六羟基黄酮2与其他几种次要化合物。根据1 H NMR，13 C NMR，DEPT 90和135，COXY，HMBC和MS推导其结构。在圆盘扩散试验中，纯净的抗菌类黄酮化合物对金黄色葡萄球菌，大肠杆菌，铜绿假单胞菌和寻常变形杆菌显示出显着的抗菌活性。抑制区为9–14 mm。与标准阿莫西林相比，浓度为200μg/ ml的化合物2对寻常型毕赤酵母（IZ = 14 mm）表现出最大抑制作用。结果表明，分离出的纯净抗菌黄酮类化合物具有显着的抗菌活性，可作为抗生素使用。这是关于从冬葵分离这些次生代谢物的首次报告。
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